Debridement Effect on Periodontal Pathogen Porphyromonas gingivalis Cultured on Titanium by Application of Atmospheric-Pressure Plasma

The debridement treatments of dental implants are very important in longterm maintenance after implant placement in a patient. Deposition of periodontal pathogens around the implant surface has a high risk of causing periimplantitis. The aim of this study was to evaluate the extent of elimination of Porphyromonas gingivalis, known as representative periodontopathic bacteria, from titanium, which has been the main material used for dental implants. Assuming that the debridement processing of dental implants removes periodontal bacteria, one of the methods for removing bacteria deposited on titanium is considered to be plasma irradiation. Irradiation with atmosphericpressure plasma was carried out against periodontopathic bacteria cultured and deposited on the surface of a titanium disk. After the plasma irradiation, the reduction of the number of bacteria re-cultured for 24 hours was evaluated. The number of viable bacteria on the titanium surface was estimated by an ATP-bioluminescent assay. Viable cells after the plasma irradiation were reduced to 1.5% or less compared to the untreated group. As one of the methods of debridement in general dental treatments, atmospheric-pressure plasma has proved to be an effective method to remove adverse prognostic factors in dental patients.